1. +1
2. +1
3. 0
I don't like 'event' or 'action' for an instantaneous thing.
'milestone' seems reasonable.
(I will again not be able to call in to the Thursday telecon.)
Curt
On 12/09/2011 01:36 PM, Luc Moreau wrote:
> Dear all,
>
> Several of you, including Satya, Tim and Jim have raised various
> concerns about events. Here are some proposals to tackle these
> concerns in prov-dm WD3. Can you express your support in the usual
> way, we will confirm the outcome at the next teleconference.
>
> CONTEXT:
>
> 1. The concept of event as defined in prov-dm is instantaneous. On the
> other hand, other ontologies define the concept of event, e.g. LODE
> [1], as not instantaneous. This causes confusion, and risks
> hampering adoption.
>
> 2. The prov-dm document (WD2) is defining 'generation' in a
> conflicting manner. On the one hand, in [2], it states that
> generation is an event, so is instantaneous. On the other hand, in
> [3], it states that completion of generation is the event.
>
> In a generation, what we care about is the point at which the entity
> becomes available for consumption by others. Before that, it's not an
> entity yet (or it is not this entity being generated). So, calling
> the whole of generation an event (forget the choice of word for now)
> is not what was intended. The event is the point at which generation
> is complete.
>
> This is actually nice reflected in Olaf and Jun's provenance
> vocabulary [4], where they have a similar concept, called Data
> Creation defined as:
>
> DataCreation is a class that represents the completed creation of a data
> item.
>
>
> Note the choice of word *completed*.
>
> PROPOSALS:
>
>
> We therefore propose to change the definition of Generation [2] as
> follows.
> - With proposals 1 and 2, resolve the conflicting definitions around
> generation (and use) in prov-dm.
> - With proposal 3, adopt another name for event.
>
>
>
> PROPOSAL 1. Adopt the following Definition for generation.
> /In PROV-DM, a generation record is a representation of a
> world event, the completed creation of a new entity by an
> activity. This entity did not exist before this event; this entity is
> available for usage after this event./
>
>
> Comment: With this, we are not saying that creation of an entity is
> the event, it's the completed creation that is an event. It's also
> also fine, I believe, to regard this as instantaneous. Also, if
> somebody wants to model the actual creation, it is also fine, they can
> use activities for that.
>
> For usage, we would take a similar approach. In the provenance
> vocabulary, they use the completed access to a data structure, but
> this is not right for what we want. Instead:
>
> PROPOSAL 2. Adopt the following Definition for usage.
> /In PROV-DM, a usage record is a representation of a world
> event: the start of an entity consumption by an activity. Before this
> event, this entity was not consumed or used in any form or shape by
> the activity, totally or partially.
> /
> Comment: These definitions are now exactly in line with those in [3].
>
>
> /PROPOSAL 3. Replace the word event by action./
>
> Comment: So, prov-dm would define four actions: entity
> generation/entity usage/activity start/activity end, which are all
> instantaneous. These actions would have "effects" on the system in
> the sense that they change the entities and activities it contains.
>
> Assuming proposal 3 is adopted, obviously, the text of proposals 1 and
> 2 would use the word 'action'.
>
>
> Can you express your support, or counter-proposals, by Wednesday
> midnight GMT.
> Assuming there is support, we would incorporate all these changes before
> XMas.
>
> Best regards,
>
>
> Luc
>
> [1] http://linkedevents.org/ontology/
> [2]
> http://dvcs.w3.org/hg/prov/raw-file/default/model/ProvenanceModel.html#dfn-Generation
> [3]
> http://dvcs.w3.org/hg/prov/raw-file/default/model/ProvenanceModel.html#types-of-events
> [4] http://trdf.sourceforge.net/provenance/ns.html#sec-DataCreationClasses
>